Aileron, flap, and dive brake



P 1952 R. E. CRANDALL ET AL 2,612,329

AILERON, FLAP, AND DIVE BRAKE Filed Nov. 13, 1948 5 Sheets-Sheet l 00'sBen/(5 MECl/AN/SM 8 A/Laav Mic/l j J INVENTORS NALD E Gen/V0421. y(/Ol/N 6; [/VA/ @mww Sept. 30, 1952 R. E. CRANDALL ET AL AILERON, FLAP,AND DIVE BRAKE I 5 Sheets-Sheet 2 Filed Nov. 13, 1948 INVENTORS ,eo/vAwClea/mm BY Jay/v c. 64 [/VA/ P 1952 R. E. CRANDALL ET AL 2,612,329

AILERON, FLAP, AND DIVE BRAKE Filed Nov. 15, 1948 5 Sheets-Sheet 5Flnpoanw Faun up CABLE -98 fup ap/mmr was: .97

raA/m/muuc l-ZAP .95 OPERATING M0 7'02 INVENTORS 100mm 5. 024N044;

Morney p 1952 R. E. CRANDALL ET AL 2,612,329

AILERON, FLAP, AND DIVE BRAKE Filed Nov. 13, 1948 5 Sheets-Sheet 4 0/1Bax: CONTROL Opzearso 8y Dive-June 502540: M45 L'waeo fizz m y R. E.CRANDALL ET AL AILERON, FLAP, AND DIVE BRAKE Sept. 30, 1952 5Sheets-Sheet 5 Filed Nov. 13, 1948 INVENTORJ' fla/vAm (kn/v0.4a BY Jami.Gmwv Patented Sept. 30, 1952 AILERON, FLAP, AND DIVE BRAKE Ronald E.Crandall and John E. Glenn, Ilos Angeles, Calif., assignors to NorthropAircraft, Inc., Hawthorne, Calif., a corporation of CaliforniaApplication November 13, 1948, Serial No. 59,848

Claims. (01. 244-42) This invention relates to airplane control systemsand control surfaces, and more particularly to a system for'controllingthe action of a single portion of the wing area so. that this portioncan act as an attitude control surface and an air brake, or as, anattitude control surface and an aileron type landing flap, or as anattitude control surface and a split-flap type landing flap.

In high speed airplanes, particularly military aircraft, devices havebeen incorporated to act as air brakes in slowing their speed and 'toaid in preventing the airplane from attaining excessive speeds duringdiving maneuvers. The name dive brake has thus been applied to suchdevices, which generally consists of one or more auxiliary surfaces orflaps which are extended into the air stream to increase the drag-forcesacting onthe airplane. However, inasmuch as higher speed airplanes tendto have thinner wing sections and smaller wing areas, the problems oflocating space for surface operating mechanisms and finding wing areafor'mo'unting the various desirable separate control surfaces themselvesbecome more difficult and in some cases impractical of solution.

It is, therefore; an object of the present in vention to simplify theproblem of wing layout and also to obtain the desired action provided byvarious movable control surfaces. Usingthe present method, the divebrake surfaces are not additional surfaces requiring extra mountingmeans and additional portions of wing area, but dive brake action isaccomplished by splitting the top and bottom panels of the aileron oneach side of the airplane simultaneously, thus producinga balanced drag.

It isia further object of this invention to provide control'systems foran airfoil combining the various functions as mentioned which can beoperable by conventional piloting procedures and controls, and which, inaddition, will not transmit erratically varying surface loads to thepilot which have to be offset by pilot control forces..-

' A pre'zfe'rreg'i specific apparatus which embodies the; abovefunctions comprisesfthe, followingmain parts; which are duplicated ontheoppositelside,

offthe'airplane: an airfoil section comprisihgan upper-and a lower panelhinged. sepanatelyat their forwardedgesto a nose section whichis in turnhinged to the wing trailing redge structure'. i.A mechanism, forrotating theentire air-'- fpilj about l the nose section, hingejlineyis;located.

in the.wing .forward oftthe surfacer A mecha-r' nism for separatingtherupper and: lower-panels:

of the airfoil about their respective hinge lines is located in the nosesection of the airfoil.

Briefly, the operation of this airfoil isas follows: as a dive brake,the surface splits half up and half down, totalling. 120 open. As aland-- ing flap, the entire surface first lowers to 30 down and thensplits open thus returning the upper panel to a'substantially fairedposition with the wing and placing the lower panel 60 down.Various'increments of surface posi-] tion as a solid landing flap can behad, 'but the split flap action has only the two positions besidesclosed; those of 60 and open. At all positions of surface whatsoever,normal aileron action can modify the basic deflection by the full rangeof aileron control in either direction from the instantaneousneutral.This range of aileron control movement is approximately 13 up and 13down, rotating about the nose section hinge line.Three,separately-operated pilot controls modify this airfoil, whichsometimes acts as a single unit and at other times as a split surfacewith upper and. lower panels. However, electrical connections betweenthe dive brake control mechanism and landing flap control mechanism aresuch as to prevent the maximum additive deflected positions of thepanels which might otherwise be possible mechanically.

The invention may be more fully understood by reference to the.accompanying drawings, shown by way of illustration and not limita tion,in which:

Figure l is a block diagram showing a cross section of a control surfaceon the trailing edge of an airplane'wing'.

"Figure 2 is a perspective diagrammatic view showing the aileronoperating mechanism of the trailing edge control surface. I I

Figure3 is a diagrammatic view showing. the dive brake operatingmechanism of the same control surface.

Figure 4 is a. longitudinal section view showing a pilots dive brakecontrol'handle.

Figure 5 is-a side elevation view showing a pilotslanding flap controllever.

' stallati'on of adive'brake-operated mechanism grammatic views showingvarious positions assumed by the trailing edge control surface.

Referring first to Figure l, an'upper' surface l and a lower surface 2of an airfoil are pivoted forwardly at their respective hinge lines 3and 4 to a nose section 5. The nose section 5 is pivoted at a nose hingeline 6 to the trailing edge structure of a wing 1. Installed in the wingI forward of the airfoil is an aileron mechanism 8 which operates torotate the nose section 5 and A ileron mechanism The aileron mechanis awin be described first. As shown in Figu're 2, apair of aileron controlcables l lead froni a pilots control stick ll, forexample, to a,cable'quadrant l2'in the left-hand outer Wing forward of the left-handairfoil to be operated. Additional aileron control cables Illa operatedby the control stick ll lead to the right-hand wing forsimultaneousopera tion of the right-hand airfoil by a system identicalin operation to the left-hand aileron'system to be described, butconnected in reverse direction for conventional aileronjcontrol. Thecable quadrant l2 is rotatably;mounted on a.fixed quadrant axis l3, and"the cables ID are, connected, one in a groove I 4 on each side of thequadrant I2 so that conventional movement of the control stick II willproducerotationalmotion of the cable quadrant l2.- Connected to aquadrant arm 15 is a control rod H in turn connected to one end of abell crank I! located inboard from the cable quadrant I2, the other endof the bell crank I 1 being rotatably mounted together with a hydraulicpiston rod terminal 18 one fixed bell crank axis |9.. A gimbal andbearing connection 20 near the outer end of the bell crank I! carries avariable length screw assembl 2! which connects at its inboard end. to avalve shaft 22 of a servo control valve 23. The servo control valve 23is contained in and fixed to the housing of a hydraulic aileronactuating cylinder 24 which carries an aileron piston rod 25 terminatingat the bell crank axis l9 as nentioned before. This servo valve 23'is'provided with fluid pressure and return connections 28 from theairplanes hydraulic power supply, and controls the direction of fluid tothe proper side of the enclosed actuating cylinder piston (not shown) 5to extend or retract'th'e aileron piston rod' 25 attached theretorelative to the aileron cylinder 24. The closed, inboard end of theaileron actuating cylinder 24 is'pin-connectedto an'operating linkagearrangement 2'! which is connected directly to the airfoil nose section5 to rotate the entire airfoil about the nose hinge line B when fluidpressure displaces the aileron actuating cylinder 24. A centering springassembly 28 is pin-connectedbetween the cable quadrant i2 and theaircraft structure 29. In

theneutral position of the controls, the centering spring center'line'is along a radius of the quadrant l2, so that movement of thecontrols to either side of neutral will introduce a "feel" to thesystem, tending to restore it to neutral.

The full-power hydraulic attitude control stirface system thus fardescribed is somewhat similar to that fully shown and claimed in aoopending application, Serial No. 23,567, filed April 27, 1948. Othertypes of full-power systems can be employed instead of the hydrauliccontrol system shown herein, such as the full-power electric attitudecontrol surface system disclosed in a co-pending application, Serial No.65,806, filed December '17, 1948', or two different types of fullpowersources can be combined, using one or the other as a stand-by system,similarly to the method shown in another co-pending application, SerialNo. 422,265, filed August 3, 1948.

Landing flap mechanism The variablezlength screw assembly 2! is attachedto a telescoping square shaft assembly 33 so that rotation of the squareshaft will turn one end of the screw assembly 2| in the gimbalconnection 20 and thus move the valve shaft22 to produceindependentdeflection of the airfoil nose section 5. In one preferred form of theinvention, this square shaft 33 is connected to an extension 34 of aseparate landing flap drive mechanism, so that lowering of the landingflaps will cause csimultaneous'lowering 'of the aileron surface at bothwingtips while still permitting normal roll control wtih the hydraulicaileron system; similarly to the method shown in a fourthpo-pendingapplication, Serial No. 57,518, filedOctober 30,-1.948: However; it isentirely possible 'to omit the separate landing flaps, mere- 1yconnecting the square shaft 33 to empower source and control of its own,and still obtain the desired landing flap action from the droopingailerons. I

-With the addition of the landing flap system extension to the aileronoperating mechanism as described above, the airfoil underconsiderationhas combined in it the function of an aileron and a landingflap. In the present apparatus, while the separate landing flap lowersto a position 50" down from normaLboth aileron surfaces lower to aposition approximately 30 down from neutral. The control signals tooperate the combination airfoil have been applied to the mechanism whichrotates the entire airfoil about the nose h-inge'line, .so that theseparate split surfaces have remained together in the closed position. e

Dive brake mechanism The dive brake mechanism located in the nosesection .5 of the airfoil on the left-handside of the airplane will nowbe described. The mechanism onithe right-hand side operates in the samemanner and both are controlled simultaneously. Installed in a lateralposition near the center of the'nose section 5 is .a hydraulic divebrake actuating cylinder35 with the customary piston (not shownyand divebrake piston rod 36, as shown in Figure 3. Neither end of this'cylindernor the piston'rod isfixed to the nose'section structure, but onecylinder end 31 is pin-con- ..eqted approximately at -fi h an les-129.ppp t njiikaa wh c f 'a 'i f e s" in a fixed b it' ageT'lthesanfleiylindeiff lus ew ch P ire' 4" nd 1.? iie' fis i e w fi n 9l i o e n Thefi rst el I. 1 ."TI i sf h h" a. l e fl te nll pfsi 2 Watt."!4- d e. e sne el ra n sts tbnqus e similari k .5.1 9 @19 re b a sehem i Theuh s direb. 19.. 4. sqlisl x L h to. 9m; ivs b. e se. srteqe. 1. nea the'hirige line 3 and projects downwardly .59 that earwarP s an i wi a e he p er su I inwar l at he tr i ing ed e The owe di...b. a eh9rn iis simi ar y at ached tQ-a ower di e-brake surieq u mists u mam x so th re w d pu h. on it w ll rot te the. pwer $3. 1 adownwardl a e t a l n e ge I dimer. w enthe aqtuatine t ne 4. i loomedtwam the d brake ac uatin c l nder .5. by hydraul c d r ss re acting, ontn m ac ion sideq t e y nder. piston the be l pra ks 4. an 2iwi11r9ta ecl ckwise. mm. he. op). and ac s mu aneou ont eunpgr and. ower. divebrase mtiaqes to sepa a e t emtt zc ii ig.to. the nbpard. end o t diyeb akeQxlind n.3,.'the.dwejbra e p ston rod .61 s con,- nected, to two. inboad; e l cranks 1 a d. 4 hese bel ranksaz each. linked toe seeond dive raehom hand on eachv dive rakesurfaee imilarly to. the. arran ement attheoutboard. end. 'm edire tiqnof operation is such that. when. the djyebrake. piston rod, 36 is;orqe.d;tqward the. dive brake actuatincylindemli by pressureactinghn the.'11Q! f% ti0n"'Si jof. e cylinder.piston, a ab ve, theiinboard bell cranks. 41. and 4.8.; will rotate.counterclockwise (from. thetop) and act. simliltaneou"slatonthepnerjland lower'zdive brake surfaces to. separate. them,incnopdration'withit outboardhell-cra'nks;4;l and. 4.2; I

"It willthus'be seien thatthefioatinghdlye. brake actuating; cylinder.35. forms. a variable-length portion of, an effiective. link between.the. inboard andfoutboardz bell cranks, and thatwhen. thislink is;contracted or. expanded, by..cy1inder.,pressur, the? dive brake surfacesLandJZ. will: be opened or. closed respectively, rotating. about;theirhifige lines 3. and" 4. Since each dive brake. surfaceihas twooperating. horns (inboard. and outboard)..,

whl'chmust move together at all timesd'ue tothe edge'structure of thewing 1;"Th'e solenoid-valve 53' has two "ports for a pressure sup'plyline'"54 and aretilrn" line '55 which some from the airplane 'shydraulic system, and two solenoids (not shown) control its operation.Normally, when both Solenolds" are deenergized; the solenoid valve 53.:is spring-controlled? in the neutral position, closed to both cylinder..closejxand .open lines. 51 and 5.2.. whenjqnervalve. o enoi ner iz d.th

fopen. cylinder. line 52 sidebf. the. control rel e a es e te at antipsand. to assume qyr rent 199.62 etiti ns i and wh n. th when We t9 bestnned eiexe ltel i ie he. 91 91. n9 it re: fore, a, ynch ni in 1 6; Fgure .0 pteiere y m lox-ed to. ee th ides n he semere eti e msiti n whenm n th s. sy tem onsist Qt 'sux ad -p erated oten iom ter. n each sideQf-the. ai pla e, the movable contac s 91- w ch areflzsed o more. withthe. urfac s and ey'e i a bridg cixcnitlwh chf ncl des a Polarized la Bosin on oi: twp: contacts. depending he d et m gcurnent flow if sur a en s tions diff 6.1T the polarize d relay-will energize. a power. relaxwhich will. break the electrical-circuit w n; an r m:

to the solenoid valve on the side of the."airplane where the surfacesarejopening. or. closingjf-aster. Thus, the v.alve m0m.entari;ly.returns .to neutral.

until the slower. side. has caught, up to where the polarized'rela'yagain opens- 'Thissynchron'izing is welljknown.

' 7. 9 5 .qea fielfdfimwt As-mentioned before, the dive brake, landingswitch 62 only-.is 'actua'ted, and wlinthe handle is released, a swit hspring" 63 "rtu1fns &1 Handle so to neutral where neither"swrpemsacmaseu;

Figuresid and 6; A"flai) "control lever s 9; uter drive lever 65;'innerdrive levertet, and flap cable pulle'y 6 1 are pivotal-1y andi'nde'per'lde'niab "inoiint ed side-by-side on a mounting bolt 68. Ator'sion spring 69 is" als centrally fiositiond ab'oiitthe mounting boltewe-tween the" inner 'dfiil lever 66 and. thefiap'eabl'ermn'eytlgi-"Theiifine'r end of this spring hasa tang.1.0....which fits into an arbor slot 7| cutout of an arbor I2constructed ilfi i lx. ith. he. inne .dr ye lever, filiiabq t. its xibiqtatiqn; II e; ute: 'endlot he, q sio SQ i. a it es qqp nto. which.fits a. drive rn. .i lx d. 9 e outer. dr ve. lever 65 ea .v so te nd! aer r hasp nglhasb en m: eade by, a. zedet imined a un oi-win mn.

' T n the neilt a in n tft fi nmntrolsn he quiiie lendsqihc th apa aga nt her tatiile q ce efi he re paded prin a. pu e a mp nflfi. whicnisfixedto. a

; Qeble' ull narm lfilaattachedltg the flancaple pulley, 6.1 infeebothdr ve. layers 'an ....bear n geinstthiS nul .rmspinifi, n roneaqh'j id r9. es t t. Q Qes; exerted on. he.' lap\.cah e lley to otate t outhelmquntinebol .631; I we e e h the ..t? -d i Y-. le er. 5

arm pin 15 tends 'to'rotate' the flap ,cable pulley 61 in the samedirection as the initial drive lever; was displaced, Assuming'the cablepulley'B'I is free to turn, it 'will reach'a new neutral position whenthe pulley armpin'15 again contactsthe end of the drive lever which wasdisplaced. l

I A lower extension 'I'! of the flap control lever 64 is provided witha, control lever pin 18 which also fits between the drive lever ends;and is for the purpose'ofconta'cting and rotating one of the drivelevers j65 for 66, depending upon which direction the flap "controllever 64 is moved. The flap cablepulle'y 'SI'is connected by flapcontrol cables I9 andfifl to a'flap operating mechanism (partly shown inFigure '7) so that the position of the flap cable pulley 01 alwayscorresponds to the instantaneous position of the landing flaps (notshown): In this manner, theflap "cable pulley can indicate relative Iposition of the flaps by carryin'g'apointer moving over a graduatedscale attached'to the aircraft structure.

7 Thus, anon rigid p'repositioning syst'em is provided; which permitsrapid movement of the flap [flaps will follow untilthe pulley arm pin 159.116.

the control'lever pin I8 reach the new neutral position at which theexternal torsional force on the flap cable pulley is removed. I i

When the flap lever 64 is rotated aft,- the pulley cables 19 and 80'willoperate a flap control valve 8I (Figure 7 to lower the separate landingflaps (not shown), and when the flap lever 64 is rotated forward, thelanding ,flaps will be retracted. Mounted on the flap cablepulley is abeveled-end cam 82 which is, arcuate in shape with its center of arc atthe center'of the pulley. A dive brake interconnectingswitch 83 mountedon a switch bracket 84 secured to the airplane structure 29 has anactuator roller 85 which rides onthe cam 82 in any position of thefiapzcable pulley 6'! except the extreme flaps upj posi-, tion, at whichposition the actuator roller.85 will runoff thecam 82 at itsbeveled-end. 80 and return the interconnecting switch 83 toits normal,non-actuated, position. This switch functions. to3rend'er the dive brakecircuit inoperative whenlthe landing flaps are lowered; as will bediscussed later; inqa description of electrical operation. H 1, V

Aileron control, is afiected .by conventional movements of the pilotscontrol stick II, as

shown diagrammaticallyin Figure 2. Electrical switches 'In order tounderstand thoroughly the opera tion of the combination airfoil of thepresentin vention, the location and physical operation of three moreelectrical switches will now be 'de-" scribed. Figure 7 shows a portion'of the sep'a-E' rate-landing flap operating mechanism. --Flapcontrolcables'lil and. 80 coming from the flap cable pulley'cI, shown inFigure 5, are attached to opposite sides of an inner groove 90 of a'flapcontrol quadrant 9|, so thatjfore-and aft forces- 8. anism onsists of athreaded screw IOI machined on the driveshaft I00. this screw turning inja'follow-upnut I02whi'ch is prevented from turning by a stationaryridge I03 fitting into a guide groove I04 in the follow-up nut I02.Thus, asthe landing flaps are raised or lowered'lbythe drive shaftlflflfthefollow-up nut 102 will move longitudinally on'the scre w' IOI,and sincethe follow-up cables 91 and 98 are attached, one to each-sideof the follow-up nut I02, these cables can, "produce rotation "or thefiapf cor' trol quad rant 91'. j

In operation from rest, whenthe flap control cables 19 and pull to theright, for example, on-the control quadrant 9i the quadrant will berotated a small amount about an ans located'at the point of tangency ofthe follow-upcables 91 and 98, since at this time the flaps haveno't'yet moved andfthe follow-up cables are stationary, Therefore, thecontrol valve rod 93 will be pulled out-"of thefiap control valve '8Ifar enough to open it to produce flapmovementin the desired direction.The valve used in the'present instance requires only /8-inch toopen-fully. Now the flaps are in motion and the'di-rection of follow-upnut I02 motion is suchthat the follow-up cables are pulling the control'quadrant to the ri'ghtalso. Assuming the control-cable motion is thenstopped at some new position, the followup cables will rotate the flapcontrol quadrant fl I about an axis located at the-point of tangency ofthe' control cables" 19 and 80. 'This, of course. moves the controlvalve rodf03 back into the valve '8l 'until the off position is reached,where the flaps/and follow-up cableswill be stoppe'dfi l 1 A switchactuatorplate I05 is installed on the flap control quadrant 9| sothat'when the quad rant is in'the flaps down position} this actuatorplate I 05 is i'noperating contact withthe plunger shaft of a landingflapswitch"I06 which is firmly attached to the airplane structure '29.Normally, this landing'fiap switch I06 isin' t'henon-actuated'positionfibut it is "adjusted tobeactu'ated when the separatelanding flaps reach a position three-degrees short of full down. .Thisswitch functions to separate the dive brake surfaces as will bedescribed later. I

The remaining two switches'to bedes'crib'ed are part of a mechanismlocated'in'the airfoil no'sesection 75. Figure 8 shows the installationof.thesemicroswitchesandalso one of the-surface-operated potentiometersto controlxthe synchronizer 56.: ".Here' the mechanism assembly consistsof a'fixed support-plate H0 mountingia crankshaft assembly-I I I'. inbearings I.I2,and" a potentiometer-I I3. -A' gear sector IM turnedbythecrankshaft II I meshes with a spur geanil I5 fixedtojthepotentiometer shaft 1 I6. .-An operate ing'crank II'I attached to the,crankshaft -;,-I;I'I- connects -'.by.,-a-'crank.-rod I I8' to the lower:dive brake surfa'ce 2 above its hingefline' 4. 'I"-hus; ;@a ll movements"of the divebrake surfacesin opening or closing will rotate thecrankshaft I-I I and thereby regulate theposition-of the potentiorn:eter-I-.I3.i, 7 S51 i. Alsorigidly attached to they crankshaft H I. aretwo. microswitch operating arms I 20 and-l 2 I the one nearer thepotentiometer I I3 being provided at its outer endwith a hollow'ba'rj'I22? into whicli 'ananch'or nut has been pressed? An anti-creepactuatorbolt I23with a lock nut I24 is installed through this anchor flat, the etire arnifarr angement being such that as the crank sha tfIII'rotats,the head 'ofithe anti creep actu'ator bolt I23 operates an a nti-crep'switch 11 face attitude at this time, after the landing flaps havereached their full down position. The dotted line positions againindicate the available aileron range from this new position. 7

It will be noted from the electrical diagram that if the pilots divebrake control handle 60 is now'operated, nothing will result, sincepower for the dive brake switches iii and 62 is stopped at theinterconnecting switch 83. In fact, no dive brake actionis obtainedduring any positions except full up or full down of the landing flaps.This prevents the lower'dive brake surface from ever deflecting to anunreasonably large angle whereit would lose its desired effects.

When the pilots landing flap leverv '64 is then moved forward toward theflaps up position, and the separate landing flaps move up atleast threedegrees; the landing flap switch I06 will then'returnto its normal,non-actuated, position as shown in the "diagramyagain applying elec--trical power to the dive brake close solenoids I31 and "l3'|a. This istrue because the interconnecting switch 83 does not return toits normalposition until the flap cable pulley 61 (Figure 5) is moved completelyforward, as previouslyde- 12 forming substantially the normal faired-incon-,- tinuation of the wing trailing edge upper surface. This isdefinitely an advantage, since it has been found that asplit-fiap'landing flap in a position 60 down contributes substantiallymore lift' than an aileron type landing'flap in a position 1,30? down,which would be the case if the dive brake surfaces were not opened atthe final moment. The action as a landing flap is, therefore, a rel'a itively slow rate of entire surface deflection down to approximately fromneutral, and then a relatively fast separation ofthe surfacesto thefinal flaps down position. While the apparatus of the pr'esent inventionis shown as applied to a. conventionaltype airplane with tail surfaces,it may easily be seen that the same method also applies to an all-wingtype airplane. In fact, for the latter type airplane, by providingseparate controls for the dive, brake mechanismlon each sideofthe"airplane, drag rudders are obtained; and by handling the aileronmechanisms similarly, elevons for both elevation and roll'controlare'obtained. Thus, all ofthef above mentioned functions can becon'ibin'e'dinto a single portion of thewing area. Since full-- I powercontrol systems are used throughout, the

scribed,-and the close circuit is now completed through theinterconnecting switch'83, landing flap switch I06, synchronizer 56,close, solenoids I31 and I311 and ground. r

Dive brake anti-creep ""An additional feature is provided in addition tothe basic system already described. It has been found that when the divebrake surfaces are closed and the solenoid control valves are inneutral,the surfaces have a tendency'tocreep'open,

due to the reducedairpressure on the upper side of" the wing. Therefore,a circuit is provided which willkeep hydraulic fluid pressure in theclose lines of the dive brake actuating cylinders. when the dive brakecontrol handle is in the neutral position. This circuit (Figure 10)consists of a wire lMl'from the non-actuatedsidei of the dive brake openswitch 6| through the anti-creep switch I25 on-the right-handidivebrake,to both close solenoids-13] and [3111. The right-hand fclose solenoid[3.1m is connected directly to theanti-creep switch I25 and the lefthandclose" solenoid I3! is connectedtfo'this switchwthrough the synchronizer156. In this mannenifwith all switches and levers in their normalpositions, power is continuously supplied to both close, solenoids, tokeep the divebrake surfaces completely closed, and avoid anydragcaiisedby' their separation. Q J A If. the dive brakes are open morethan 5, however, this additional circuit is broken bythe anti -creepswitch I25 as describedbeforepsince obviously it is, not desirable tohaveitli dive brakes "return to the closed position afterjust openingthemand letting the, dive bralge control handnretur'n to t r neutralposition. V

v, Summary ;A" fi lPf i e l f he. i li inventmnn wfiihW 1 jbeaena e tmzt regoinais the.

sequence; of useof; the combination airfoil as :a.

landing'flap F partialpercentages;oflanding,,

flapjdeflection, "the" surface acts as an ordinary aiieron-type f flap;Q'Ifhis' occurs throughout the range 'ofjfrorn '0?to approximately 310?down. From this point. 11,: as "for I the fun" sewn positiori of thelandingflapsi the surface acts as r a; split flap type landingflap, withthe" upper panel? pilot is not called upon to resist, any of the surfaceloads resulting from the, variations of surface deflection.

In the present embodiment of the invention, merely a centering spring isprovided to neutralize the aileron control; however, when the principlesand means shown herein are applied to elevons on an all-wing airplane, asynthetic feel. responsive to air speedyor normal acceleration is.preferredin the pitch of elevation control system.

What'is claimed is: I 1. In a control system for an aircraft,a controlsurface on opposite sides of said aircraft, each said surfacefcomprising.a nose section hinged to. said aircraft and superposed upper and lowerpanels each hingedfto the rear of said nose section; surface power meanspositioned outside of said .lcontrol surfaces and c'or'intzted to rotatesaid controls'urfaces abouttheir respective nose section hinges, flapcontrol means connected to said surface power means to move saidcontrol. surfaces in the same direction simultaneously, between neutraland down positions ,--flap follow,- up means connected to said flapcontrol. means. to move in exact accordance with said control surfacesas moved by said flap control' means, electrically controlled hydraulicpanel power means positioned in eacliof'said nose'f'sections andconnected respectivelyltlojeach of said [up I and lower panels" inoppositely 'mov'ing re non;

shipto' move said panels between open and closed, positions; electrical;switghil g "means electrically connectedto energize said panel" powernieansxing the -approximate reaching; of said own by saidcontrolsurfacesfand to n {5128531 I I v ctionup on -th approximate leaving of sd down position 'by'fs aidv control surfaces. 'j

2. Appar atus in ace ance. W h claim eluding-aileron. control":meansadditional nectedto said 'surface power, zneans tomgve ai i controlsurfaces in opposite directions simult ne 3 ously, independent ofmovement 0 sa surfaces by said flap cont I, mean l3 trol surface onopposite sides of said aircraft, each said surface comprising a nosesection hinged to said aircraft and superposed upper and lower panelseach hinged to the rear of said nose section, surface power meanspositioned outside of said control surfaces and connected to rotate saidcontrol surfaces about their respective nose section hinges, flapcontrol mean connected to said surface power means to move said controlsurfaces in the same direction simultaneously between neutral and downpositions, flap follow-up means connected to said flap control means tomove in exact accordance with said control surfaces as moved by. saidflap control means, electrically controlled hydraulic panel power meanspositioned in each of said nose sections and connected respectively toeach of said upper and lower panels in oppositely moving relationship tomove said panels between open and closed positions, electrical controlswitching means electrically connected to energize both said panel powermeans in either the open or closed direction, said control switchingmeans located to be mechanically operated by movement of said flapfollow-up means to energize both said panel power means in said open.direction upon the approximate reaching of said down position by saidcontrol surfaces and to energize both said panel power means in saidclose direction upon the approximate leaving of said down position bysaid control surfaces, manual panel control means also electricallyconnected to energize both said panel power means in either the open orclosevdirection, and follow-up switching means electrically connected toselect energization control of both said panel power means either bysaid control switching means alone or by said manual panel control meansalone, said follow-up switching means being mechanically connected tosaid flap follow-up means to select said control switching means as theoperative path when said control surfaces are moved by said flap controlmeans to any position except said neutral and to select said manualpanel control means as the operative path when said control surfaces arepositioned in said neutral by said flap control means, where'- by manualseparation control of said upper and lower panels is provided at alltimes when said flap follow-up means is in saidneutral and automaticseparation control of said upper and lower panels as set forth above isprovided at all times when said flap follow-up means is in any positionexcept said neutral.

4. Apparatus in accordance with claim 3 ineluding aileron control meansadditionally connected to said surface power means to move said controlsurfaces in opposite directions simultaneously, independent of movementof said control surfaces by said flap control means.

5. A control system for operating a split-flap type aircraft dive brakehaving superposed flaps rotatably hinged to a hinge-mounting structure,which comprises two upper links rotatably attached to the upper flap ofsaid dive brake on one side of the hinge line thereof, two lower linksrotatably attached to the lower flap of said dive brake on the oppositeside of the hinge line thereof with respect to the direction ofattachment of said upper links from said upper flap hinge line, firstcrank means pivotally mounted on said structure and rotatably connectedto one of said upper links and to one of said lower links on the sameside of the mounting pivot of said first crank means, second crank meanspivotally mounted on said structure and rotatably connected to the otherupper link and to the other lower link, said other two links beingconnected to said second crank means on the opposite side of themounting pivot thereof from that of the link connections to said firstcrank means, an extensible linkage rotatably connected at each endthereof to said first and second crank means, respectively, afree-floating hydraulic piston and actuating cylinder assembly connectedwithin said extensible linkage, a four-port electrical solenoid-operatedcontrol valve, flexible alternate open and close lines operativelyconnecting said valve to said piston and cylinder assembly, a hydraulicpower supply system, and pressure and return lines connecting saidhydraulic system to said four-port control valve, whereby said divebrake flaps are opened and closed quickly by means of the fast action ofsaid control valve.

RONALD E. CRANDALL JOHN E. GLENN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name I Date 2,173,538 McKellar Sept. 18,1939 2,254,304 Miller Sept. 2, 1941 2,279,615 Bugatti Apr. 14, 19422,376,731 Stoner May 22, 1945 2,422,035 Noyes June 10, 1947

